Treatment of hydrocarbon solutions of oxygenated chemicals



United Statesv Patent 2,943,104 TREATMENT OF HYDROCARBON. SOLUTIONS OF OXYGENATED CHEMICALS Neal M.'Caruthers, Tulsa, Okla., 'assiguor to Pan American Petroleum Corporation, Tulsa, Okla., a corporation of Delaware Nb Drawing. Filed May '8, 1957, S01. No. 657,738 5 Claims. (Cl. 2 0-440;

*Ihe present invention relates -to a novel process {or improving the quality of hydrocarbons recoverable from hydrocarbon-oxygenated chemical mixtures. More particularly, it is concerned with the recovery of terrnin'al or from "solutions thereof containing oxygenated organic chemicals 7 H I The hydrocarbon phase produced by the reduction of carbon monoxide with hydrogen in the presence of a fluidized catalyst, particularly an iron catalyst'," is made up primarily of terminal olefins, i.e. at least aboiit 75 percent of the hydrocarbons in said phase are erminal olefins. In order tornak e high quality'motorjfuels from this hydrocarbon phase, however, the {oxfygeriated compounds must either be rcmoyed at converted into olefins by deoxygenation and the entire bless om-.

diesel fuels, the Jolefins, the bulk of which are nonterminal raw material fo r chemical synthesis since the types of {chemicals derivable from terminal olefi is are much more in structure, -i ;e.int er-nal 'olefinsfdo not serve -as a good useful than those produced frorn' theirnonterminal i50 V iners. Thus, iffit iscle'sjired to recover a substantially pure stream of terminal olefins from a hydrocarbon synthesis. oi1 phase, it has generally, been desirablc'to recover at vleast a portion of the chemical saidphase prior to the "su'li'sfiiiii'eiit transmit er the T' to obtain the, desired 't'e'rminal-olefins. Tliefoil fraction producedin the now generally known modification'of tlie Fischer-Trgpsch'syn thesis has a significant content of chemicals, such as acids,- rabies; Hyde's 'aaaalaenz s'ta'gaiier with a relatively small proportion of esters. For example, in a hydrocarbon synthesis plant 'designedto produce6,000 barrels per day of liquid' hydrocarbdn's, there are 320,000 pounds per day of oil-soluble che ,The distribution of these chemicals ih the oil stream breaks downla s rolloiis'fs: 100,000 pdl'inds6foarbyl"coriipfirids, 1 0 0 0 0 10 610... 0.000.,s0 sisa ea e 30,000 pounds of esters. Owing to their value as chemicals, it is desirable to separate foxyg'enated componds as completely as possible from the oil stream. A1-

about g was accompanied by extensive shifting of the terminal of water given ofl during deoxygenation failed to appear. 7 I then undertook a study of the eifect of Water content v so, in the subsequent utilizationof the olefinicjhydican' 1866s ftsrgeliernieal syatneses, it }-is imperative tli'a't thes oxygenates be removed from the oil to avoid catalyst persisting er "contamination of thep In recovering oil-"soluble chemicals? solutions thereof, such as for examplihydrocarhiiii solu 2 v tioiis of the type produced by the reaction of carbon monoxide with hydrogen at elevated temperatures and pressures in the presence of a fluidized alkali promoted ironcatalysL'ithas been'proposed that aqueous soap solutions or various types be employed as selective solvents or extractants for such chemicals. 7 Generally, these soap solutions are not composed of soaps in the "ordinary sense, but are made uplargely of substantiall'ynonsurface act'ive salts of alkali metals or equivalent salts derived from carboxylicacid mixtures having an average molecular Weight ranging from about to about 155. soap solutions of this type are most conveniently prepared by adding the required amount of an aqueous solution of caustic, or other suitable b286, to the primary oil traction produced in hydrocarbon synthesis whereby the free acids present infsaid fraction are neutralized. A substantial proportion "of the oil soluble chemicals, containing about 5 to 10 Weight percent of hydrocarbons, is solubiliied in the soap solution. w

Accordingly, it is an objectof my invention to "provide a method forconvertin'g the oxygenated chemicals found in the aforesaid hydrocarbon phase to terminal olefins without simultaneously fisomeriiing the terminal ole'firis originally present in said phase. It is another object of my inver'it'ion'to provide ondition's' 'for securin conversion of said chemicals into terminalole'fin's without subsequent alteration and under conditions favoringa long and active catalyst life. It is a'further object of my invention to provide a means for treating hydrocarbon solutions of the above mentioned variety whereby a substantially chemical 'fr ee hydroe arbon solution is obtained having a maximumteriminal olefin content, such object being accomplished without the use of expensive soap extraction or similar methods.

'In carrying out the process of my invention I subject a terminal olefin-containing hydrocarbon solution of oxy-. genated chemicals to a deoxygenation step in the presence of an activated alumina, specifically, a-alumina monohydrate. The conditions used in efiecting deoxygenation of the chemicals present in the hydrocarbon solution are essentially equivalent to those previously used. However, the process of my invention differs from prior deoxygenation techniques inrthat I regenerate the catalyst under conditions unlike those formerly employed. The basis for this novel method of regenerating and conditioning the catalyst resulted from observations I made during the early stages of my work on this problem. Thus, I found that with a-alumina monohydrate good removal of chemi- "cals, i.e., deoxygenation, from their hydrocarbon solutions with very little, if any, shifting of the olefinic bond occurred during the first use cycle of the catalyst. However, when I regenerated the catalyst by burning off the carbonaceous deposits thereon with temperatures in the range of 600 C. and resumed treatment of said hydrocarbon solutions, deoxygenation was still excellent but olefinic bond toward the center of the carbon chain.

Shifting of the double bond seemed to discontinue, how- 7 after an initial period. Simultaneously with this result during such period I noted that the usual amount "of the' catalyst on this double bond shift. This investigaaen showed that if the regenerated catalyst was saturated with water at about 300 to about 350C. the 5 double bond shifting would not occur. If no such treat-r -mnt was made, i.e. the catalyst was left in its dehydrated condition, after the high temperature regeneration step,

sufficient water to become saturated.

In practicing my invention catalyst which has become substantially inactive in the deoxygenation reaction 1s 4 of Alcoa F-l alumina, the X-ray diffraction pattern of which indicates that it is u-alumina monohydrate, was charged to a Pyrex glass tubular reactor 10 inches long and /1 inch in diameter. The reactor containing the first subjected to a regeneration step involving burning off 5 catalyst was then immersed in a molten metal bath mainthe deposited carbon at a temperature of about 600 C. tained at a temperature of about 305 C. The catalyst had Thereafter, the catalyst is contacted with steam at a teman average particle size of from 8 to 14 mesh and analyzed perat'ure in the range at which deoxygenation is carried as follows: out, i.e. from about 300 to about 350 C. until the Percent catalyst is saturated with water. Treating temperatures A1 0 92 up to about 400 C. may be used if steam is added to the M1 0 0.8 oil vapor passing over the catalyst; however, such large R 0, 0.12 quantities of steam are required at this level that it is not SiO 0.09 ordinarily desirable to operate at temperatures much Loss on ignition 6.8 above 350 C. After the catalyst has been saturated 15 with steam under the aforesaid conditions, it is ready for fl 3 3 hydrocarbo; 2 3 gig f g further contacting by the hydrocarbon solution to deoxya f an over ea en g b t 2 genate the chemicals present therein. The deoxygenation so u i i g ie a on step is continued until the presence of oxygenated chemia pressure 6 1s 1 a recovery cals is again detected in the product. The regeneration 'Welght percent of the charge and am as follows and steam treatment steps are then carried out and the S ifi gravity 20 4 0,752 above cycle repeated. Alcohol, meq./g. 0.86 lixperrments have been undertaken to determine the carbonyl, 0 59 ability of materials other than a-alumma monohydrate to Ester, meq/g 0.13 deoxygenate such hydrocarbon solutions without shifting 25 Acid, 0 3 the double bond 1n the terminal olefins present. Ex- Weight percent hydrocarbons 75 amples of such materials are different forms of 'y-alumma, Cyclocel, which is bauxite (aluminum oxide) with not Space VelOeltleS of from t0 gram 0f the fleshed more than about 10 percent silica, etc. However, Ihave 011 feed per hour per ml. of catalyst bulk volume were found that none of these materials is capable, even with p ye steam treatment after regeneration, of deoxygenatingthe in th s part1cular experiment two different sets of conchemicals in the aforesaid hydrocarbon solutions without 'dltlOIlS Were used- The fir run W s m de to demonstrate causing substantial shifting of the olefinic bond. the beneficial effect Obtained y saturating the catalyst. The process of my invention will be better understood after regeneration, with water at reactlon temperature. by ref re t h fgllowing examples Run 2 compares the effect of a dry unsteamed catalyst EXAMPLE I 'on terminal olefin content in the product. In Run 1 the catalyst shown in the table below was subjected to four Neutral oil, prepared by neutralizing primary oil from complete cycles, a cycle constituting a use and a regenerahydrocarbon synthesis with an aqueous 20 percent caustic tion period. In Run 2 the catalyst was used for two solution, was used in this run. Sixty-two grams (67 ml.) complete cycles.

Table 1 Run 1 Run 2. Aggregate Samples trom Aggregate Samples from 4 Cycles 2 Cycles Test Period 1 2 3 i 1- 2 a" Total Flows, grams:

Feed 51.0 00.3 58.6 27.9 210 20.

100.0 100.0 100.0 100.0 100.0 100.0 Hydrocarbon Product Analyses:

Alcohol removal, M01 Percent-... 100 100 96 100 100 100 Carbonyl removal, M01 Percent-. 91 99 93 100 100 100 Terminal olefin concentration,

11, 89 83 84 87 05 Terminal Olefin Recovery: 1

Percent of Feed 110 104 107 p 105 107 1 Terminal olefin recovery, as weight percent of terminal olefins in feed equals Where:

catalytic; ability to deom'genate lwithout. causinga loss in .plefincontent. In each, case the catalyst was treated with non. The conditions usedand the results. obtained are shownin the table below:

Table "II lat-alumina monohydrate, .e,g.,f' 200 mesh?feed in vapor jform is ,introduced'at aspace velocity ranging from"0'.'6 to 1.3 grains of feed-per ml'. of;catalystper hour. Catalyst is continuou'sly'jbled oflf from the reaction zoneltoa regenerating, unit and after regeneration. treated with steam asdescribed above. and then returned to thevessel jinwhich'deoxygenation is occurring. .I claim: g 'Llnacontinuous process for theldeoxygenation of oxygenated chemicals dissolved in alhydrocarbon solution comprisingat leastone liquidlterminal olefin,'thc ,improvementwhich comprises contacting the solution of said chemicalsand hydrocarbons in a reaction zone with substantiallypure a-alumina monohydr'ate at a.temperateam after regeneration. in, accordance with my inven- '15 ,ture ranging. from about 300 to. about 350" C. until the presence of saidchemicals is detected inthe efiiuent from .sfaid zone, thereafter discontinuing flow-of said chemicals :oA'raLY'rro' V.A1?OR'IEHASE'11EOXYGENALIONOF- NEUTRAL srN'rHEsrs-omrmc'rroNs OPERATING .DATA. AND INFRARED: SPECTROPHOTOMETEBL DATA Catalyst Flow Rates :Conversions Temp, Test Bpa ce Alcohol, Carbonyl, Terminal Run No. Vol., *0. Period Feed, Velocity, M01 M01 Olefin,

Kind ml. g. g.'/Hr./ml. Percent Percent' Relative of catalyst Decrease Decrease Conc.,Mol I 7 Percent 1 Q .100 s4 ,16' ?Y c a t .43.4 1.1 iSSi Z? it I. ,4 as 40 .70 a 1a 1 .99 7 9s 11 Alcoa H151* as. macsg 4 100 91 14 1 15.5 1.03 100 100 24 a A1co F-* 60 305 3, it; {ES 13g. 33 if 4 15.8 1.05 100 64 72 1 15.1 1.04 100 100 4 4 Alcoa F-er 58 305 g g; 4 15.3 1.06 100 71 21 These catalysts, which are all indicated by X-ray difiraction to be anhydrous -elumina, have the following analyses:

F-6 F-10 H461 AhO- 88. 96. 85. NazO 0. 76 0.10 2.0 Fe1O- 0. 11 0.05 0. 810- 0. 08 0. 10 6. 3 Loss on ignition to 1,l00 C 8.5 3. 0 6. 2 00C 2. 2. 0 Surface area, sq. meters/g 200 350 It will be appreciated from the foregoing description that the process of my invention is applicable for treatment of a wide variety of hydrocarbon solutions of oxygenated chemicals in which it is desired to efiect such deoxygenation without bringing about a shifting of the point of unsaturation in the olefins present. While the p and hydrocarbons through said zone, subjecting said process described above may be used instead of the soap extraction method previously referred to for removing chemicals from hydrocarbon solutions, it also may be used to remove the last traces of chemicals in the hydrocarbon raflinate stream obtained from soap extraction, where it is desired both to secure maximum chemicals recovery and a hydrocarbon stream having a high concentration of terminal olefins. Acid-containing feeds, such as bydrocarbon synthesis primary oil likewise may be used; however, it has been my observation that the catalyst life, under such circumstances, is rather short, possibly due to the formation of salts which tend to plug the catalyst pores. It will further be appreciated that in adapting my invention to continuous methods, a multiple bed system may be employed in which one or more fixed beds are being regenerated and conditioned while others are being used in the production portion of the cycle. Also, fluid bed operation is contemplated within the scope of this invention. Thus, with a fluid bed of finely divided alumina to a temperature above about 600 C. in the presence of an oxidizing gas whereby deposited carbon is burned off of said alumina, next contacting the latter with steam at a temperature of from 300? to about 350 C. until said alumina is saturated therewith, and thereafter repeating the above cycle.

2. In a continuous process for the deoxygenation of nonacid oxygenated organic chemicals dissolved in a liquid terminal olefin, the improvement which comprises contacting the solution of said chemicals and olefins in a'reaction zone with a bed of substantially pure granular j lac-alumina monohydrate at a temperature ranging front about 300 to about 350 C. until the presence of said chemicals is detected in the efiiuent from said zone, thereafter discontinuing flow of said chemicals and hydrocarbons through said zone, subjecting saidalnmina to a temperature above about 600 C. in the presence of an oxidizing gas whereby deposited carbon is burned off of i said alumina, next contacting the latter with steam eta temperature of from 300 to about 350 C. until said alumina is saturated therewith, and thereafter repeating l the above cycle.

3. In a continuous process for the deoxygenation of L i oxygenated organic chemicals dissolved in a hydrocarbon solution comprising at least one liquid terminal olefin,

- thereafter discontinuing flow of said solution through said zone, subjecting said alumina to a temperature above about 600 C. in the presence of an oxidizing gas whereby deposited carbon is burned ofi of said alumina, next contacting the latter with steam at a temperature of from 300 to about 350 C. until said alumina is saturated therewith, and thereafter repeating the above cycle.

4. In a process for recovering a stream of substantially chemical free hydrocarbons containing at least one liquid 'terminal olefin from a mixture of nonacid oxygenated fatty acid salt, said salt being derived from a preferentially oil-soluble carboxylic acid, to obtain a hydrocarbon rafiinate containing said at least one olefin and a decreased concentration of said chemicals, the improvement which comprises contacting said raflinate in a reaction zone with substantially pure walumina monohydrate at a temperature ranging from about 300 to about 350 C. until the presence of said chemicals is detected from the eflluent in said zone, thereafter disf' continuing the flow of said hydrocarbons and chemicals through said zone, subjecting said 'alurhi'n'ajtbh a temperature above about 600 C. in the presenceofan oxidizing gas whereby deposited carbon is burned off of said alumina, next contacting the latter with steam at a temperature of from 300 to about 350 Cruntil said alumina is saturated therewith, and thereafter repeating the above cycle.

5. In a process for recovering a stream of substantially chemical free hydrocarbons comprising at least one liquid terminal olefin from the nonacidic oil phaseobtained by neutralizing the hydrocarbon layer produced by the reaction of carbon monoxide with hydrogen in the presence of an iron catalyst, the improvement which comprises contacting a mass of substantially pure aalumina monohydrate with said phase in a reaction zone at a temperature ranging from about 300 to about 350 C. until the presence of said chemicals is detected in the efiluent of said zone, thereafter discontinuing flow of said phase through said zone, subjecting said alumina to a temperature above about 600 C. in the presence of'an oxidizing gas whereby deposited carbon is burned off of said alumina, next contacting the latter with steam at a temperature of from 300 to about 350 C. until said alumina is saturated therewith, and thereafter repeating the above cycle.

References Cited in the file of this patent UNITED STATES PATENTS 2,754,314 McGrath July 10, 1956 2,816,906 Gilbert ct al. Dec. 17, 1957 OTHER REFERENCES Thermal Transformation of Aluminas and Hydrates, Stumpf et al., 1nd. and Eng. Chem, vol. 42, 1950, pages 1398-1403. r 

3. IN A CONTINUOUS PROCESS FOR THE DEOXYGENATION OF OXYGENATED ORGANIC CHEMICALS DISSOLVED IN A HYDROCARBON SOLUTION COMPRISING AT LEAST ONE LIQUID TERMINAL OLEFIN, SAID SOLUTION HAVING BEEN PRODUCED BY THE REACTION OF CARBON MONOXIDE WITH HYDROGEN IN THE PRESENCE OF AN IRON CATALYST, THE IMPROVEMENT WHICH COMPRISES CONTACTING SAID SOLUTION IN A REACTION ZONE WITH SUBSTANTIALLY PURE A-ALUMINA MONOHYDRATE AT A TEMPERATURE RANGING FROM ABOUT 300* TO ABOUT 350*C. UNTIL THE PRESENCE OF SAID CHEMICALS IS DETECTED IN THE EFFLUENT FROM SAID ZONE, THEREAFTER DISCONTINUING FLOW OF SAID SOLUTION THROUGH SAID ZONE, SUBJECTING SAID ALUMINA TO A TEMPERATURE ABOVE ABOUT 600*C. IN THE PRESENCE OF AN OXIDIZING GAS WHEREBY DEPOSITED CARBON IS BURNED OFF OF SAID ALUMINA, NEXT CONTACTING THE LATTER WITH STEAM AT A TEMPERATURE OF FROM 300* TO ABOUT 350*C. UNTIL SAID ALUMINA IS SATURATED THEREWITH, AND THEREAFTER REPEATING THE ABOVE CYCLE. 